// +build stm32f7x2

package machine

// Peripheral abstraction layer for the stm32f407

import (
	"device/stm32"
	"runtime/interrupt"
)

func CPUFrequency() uint32 {
	return 216000000
}

//---------- UART related types and code

// UART representation
type UART struct {
	Buffer          *RingBuffer
	Bus             *stm32.USART_Type
	Interrupt       interrupt.Interrupt
	AltFuncSelector uint8
}

// Configure the UART.
func (uart UART) configurePins(config UARTConfig) {
	// enable the alternate functions on the TX and RX pins
	config.TX.ConfigureAltFunc(PinConfig{Mode: PinModeUARTTX}, uart.AltFuncSelector)
	config.RX.ConfigureAltFunc(PinConfig{Mode: PinModeUARTRX}, uart.AltFuncSelector)
}

// UART baudrate calc based on the bus and clockspeed
// NOTE: keep this in sync with the runtime/runtime_stm32f7x2.go clock init code
func (uart UART) getBaudRateDivisor(baudRate uint32) uint32 {
	var clock uint32
	switch uart.Bus {
	case stm32.USART1, stm32.USART6:
		clock = CPUFrequency() / 2 // APB2 Frequency
	case stm32.USART2, stm32.USART3, stm32.UART4, stm32.UART5:
		clock = CPUFrequency() / 8 // APB1 Frequency
	}
	return clock / baudRate
}